MY DAUGHTER AND I HAVE JUST PLACED SLATE AROUND THE FIREPLACE AND BOOKCASE IN HER CONDO. THE WALL THAT CONTAINS THEM PROJECTS APPROXIMATELY A FOOT OUT FROM THE WALL AND IS 10 FEET ACROSS. WE WANT THE MANTLE TO SPAN THE 10 FEET ACROSS THIS WALL.
THE MANTLE WILL BE 6 INCHES WIDE AND WE WANT IT TO BE 3 INCHES DEEP. IT WILL BE STAINED A GOLDEN OAK COLOR. THE MANTLE WILL HAVE NO ADORNMENTS. MY PLAN IS TO SCREW A 2 X 2 TO THE STUDS TO HOLD CABINET QUALITY PLY WOOD TOP AND BOTTOM. THE MANTLE IN ESSENCE WILL BE A HOLLOW BOX WITH WITH INTERIOR BRACING EVERY 16 INCHES.
MY QUESTION IS; WILL THE TWO BY TWO BE ENOUGH SUPPORT TO HOLD THE MANTLE? WE WANT THE LOOK OF THE MANTLE TO FLOAT AND NOT HAVE ANY OUTWARD SUPPORT TO APPEAR. WILL IT WORK?
Replies
TURN OFF THE DANGED CAPS LOCK KEY.
Yes it will work. Essentially you are building a torsion box. Use a quality piece of 2x2 for the support, not the typical 2x2 you buy at HD or Lowes. Build the shelf on the floor before attaching it to the 2x2. Use the same 2x2 material for the interior braces, and it will slip over the wall bracket. You might consider making it a 2x2-1/2 so there's no question which way it goes. In a torsion box, precision counts. Glue all the pieces together, especially the interior braces to the top and bottom skins.
Consider using baltic birch plywood, which you would get from a hardwood or plywood dealer. It is high quality plywood without voids. Since you're going 10 ft, use two layers of 1/4 or 3/8 ply with the joints staggered. Or if you can find 10 ft plywood in your choiuce of wood, try that.
Once the mantle is built and the glue is dry, just slip the box over the wall bracket and add a couple of screws top & bottom.
There was a nice article in FWW about 10-11 years ago that had details about building torsion boxes. It might be worth your time to try to get a copy. Do a search at the FWW home page for torsion box.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
Edited 6/15/2004 9:14 am ET by Ed Hilton
It will work. 6" should not be a problem as long as it won't be supporting stone sculptures or the like. I normally like to build the box on the ground and slide it over the wall brace but that would prove tricky for a mantle this long.
For your project I would first glue and fasten the bottom piece to the 2x2 and support it on legs to keep it nice and straight then build up from there.
If the wall is bowed you may have to scribe to get a tight clean fit.